Peters Riccarda, White David J, Cornwell Brian R, Scholey Andrew
Centre for Human Psychopharmacology, Swinburne University of Technology, Melbourne, VIC, Australia.
Centre for Mental Health, Swinburne University of Technology, Melbourne, VIC, Australia.
Front Aging Neurosci. 2020 Jan 31;12:8. doi: 10.3389/fnagi.2020.00008. eCollection 2020.
The hippocampus features structurally and functionally distinct anterior and posterior segments. Relatively few studies have examined how these change during aging or in response to pharmacological interventions. Alterations in hippocampal connectivity and changes in glucose regulation have each been associated with cognitive decline in aging. A distinct line of research suggests that administration of glucose can lead to a transient improvement in hippocampus-dependent memory. Here, we probe age, glucose and human cognition with a special emphasis on resting-state functional connectivity (rsFC) of the hippocampus along its longitudinal axis to the rest of the brain. Using a randomized, placebo-controlled, double-blind, crossover design 32 healthy adults (16 young and 16 older) ingested a drink containing 25 g glucose or placebo across two counter balanced sessions. They then underwent resting-state functional magnetic resonance imaging (rs-fMRI) and cognitive testing. There was a clear dissociation in the effects of glucose by age. Magnitude change in rsFC from posterior hippocampus (pHPC) to medial frontal cortex (mPFC) was correlated with individual glucose regulation and gains in performance on a spatial navigation task. Our results demonstrate that glucose administration can attenuate cognitive performance deficits in older adults with impaired glucose regulation and suggest that increases in pHPC-mPFC rsFC are beneficial for navigation task performance in older participants.
海马体在结构和功能上具有不同的前部和后部。相对较少的研究探讨了这些部分在衰老过程中或对药物干预的反应中如何变化。海马体连接性的改变和葡萄糖调节的变化都与衰老过程中的认知衰退有关。一项独特的研究表明，给予葡萄糖可以导致海马体依赖性记忆的短暂改善。在这里，我们特别关注海马体沿其纵轴与大脑其他部分的静息态功能连接（rsFC），以探究年龄、葡萄糖与人类认知之间的关系。采用随机、安慰剂对照、双盲、交叉设计，32名健康成年人（16名年轻人和16名老年人）在两个平衡的实验环节中分别摄入含有25克葡萄糖的饮料或安慰剂。然后他们接受静息态功能磁共振成像（rs-fMRI）和认知测试。葡萄糖的作用在年龄上存在明显的分离。从后海马体（pHPC）到内侧前额叶皮质（mPFC）的rsFC幅度变化与个体葡萄糖调节以及空间导航任务的表现提升相关。我们的结果表明，给予葡萄糖可以减轻葡萄糖调节受损的老年人的认知表现缺陷，并表明pHPC-mPFC rsFC的增加对老年参与者的导航任务表现有益。
